System for uniform distribution of ventilating air and sound energy



n Jan. 1, 1954 G. K. RAIDER 2,530,335

SYSTEM FOR UNIFORM DISTRIBUTION OF VENTILATING AIR AND SOUND ENERGY Filed Jan. 2a, 1948 2 SHEETS-SHEET 1 N\ V k Jan. 1, 1952 e. K. RAIDER SYSTEM FOR UNIFORM DISTRIBUTION OF VENTILATING AIR AND SOUND ENERGY 2 SHEETSSHEET 2 Filed Jan. 26, 1948 MWONW WM) M9 Patented Jan. 1, 1952 SYSTEM FOR UNIFORM DISTRIBUTION OF VENTILATING AIR AND SOUND ENERGY George K. Raider, Chicago, 111., assignor to The Pyle-National Company, Chicago, Ill.,a corporation of, NewJersey Application January 26, 1948, Serial No. 4,368

This invention relates'to an improved acoustical arrangement for ventilated spaces, and partlcularlyto a loudspeaker arrangement for a railway car or the like by which the uniform distribution of sound energy throughout the entire length of the car may be obtained with a minimum number of loudspeaker units.

It has only been in recent years that public address, radio and inter-car communication systems were introduced in railroad operations. Such'systems necessarily required the incorporation of one or more loudspeakers in the railway car to transmit sound energy to the occupants of the car.

Due to the fact that this was a new innovation in railway passenger car travel, not too much thought was given to the matter of proper sound distribution and the first installation in passengercars consisted of locating the speakers within the main body of the car, generally utilizing aspeaker at each end of the car. With such an arrangement, an extremely poor distribution of sound energy'throughout the car resulted. Those passengers seated near the ends of the car were subjected to discomfort due to excessive noise while the sound energy reaching those at the center of the car' was barely at the audible level. In attempts to overcome this condition, additional speakers have'been added at intermediate locations throughout the car length but always suchspeakers have been disposed within the body 'of'the car and delivered their output to the car interior directly. For satisfactory sound energy distribution, it was f'ound'necessary to use, in general, from four to eight loudspeakers, depending on the quality of distribution desired. Suchlarge number of loudspeakers not only substantially increased the installation cost but naturally the servicing costs also increased in direct proportion to the number of speakers used. Furthermore, by virtue of the fact that each of the speakers was mounted directly within the interior of the car, a. modification ofthe interior walls of the car had to Poe-accomplished to provide recess -for mounting such speakers, so as to maintain a uniform and attractive interior appearance.

'While the above problem of proper sound distribution became particularly acute in railway car installations, those skilled in the art will recognize that the same problem has existed for many years in anylarge room area, such as auditorlums or assembly halls. In' fact, in any room area-sufliclently'large to dispose one ormore persons at substantially greater distances from a loudspeaker than the remainder of the occupants 1 Claim. (CL. 181-30).

of'the room, the problem of proper-sound distribution'immediately arises.

In accordance with this invention, the problem of adequate sound distribution in railway cars or other large room areas has been very satisfactorily and economically solved by utilizing a certain form of ventilating arrangement for distributing the sound energy from one or more loudspeakers throughout the room area supplied by the ventilating system. In particular, this invention provides unusually desirable results when employed in conjunction with ventilating systems of the type disclosed in U. S. Patents Nos. 2,172,771 to Norris, 2,251,682 to Leadbetter and 2,304,628 to Damerel. In all of the ventilating arrangements disclosed in the above mentioned patents, the distribution of ventilating air throughout a; room area, such as the interior of a. railway car, is accomplished in such manner as to provide a substantially uniform flow of ventilating air throughout the entire room area and without producing any detectable drafts. By incorporating a loudspeaker in the path of the ventilating air stream, yet located exteriorly of the room area serviced by the ventilating system, this invention accomplishes a uniform distribution of sound energy throughout the room area and provides an adequate sound energy level throughout the entire room area with a, much smaller number of loudspeaker units than has been heretofore possible.

' Accordingly, it is an object of this invention to-provide an improved loudspeaker arrangement for ventilated spaces, particularly for railway cars orsimilar room areas havingventilating arrangements for producing a uniform'fiow of ventilating air throughout the entire interior of the room area.

A particular object of this invention is to provide an improved loudspeaker arrangement for a railway car wherein the entire interior of the car may be supplied with, a substantially uniform level of sound energy through the utilization of not-more than two-loudspeakers located in the plenum chamber of the ventilating system ofthe railway car.

The specific nature of this invention, as well as other objects and advantages thereof, will become'apparent to those skilled in the art from the following detailed description, taken in conjunction with the annexed sheets of drawings which, by way ofqpreferred exampleonly, 111118? trate-a preferred-embodiment of the inventionon thedrawingsf Figure -1 is a partial, longitudinal vertical-sew tional view of a railway car incorporating a loudspeaker arrangement embodying this invention.

Figure 2 is an enlarged scale transverse sectional view taken on the plane II--II of Figure 1.

Figure 3 is a still further enlarged sectional view taken on the plane III-III of Figure 2.

Figure dis a sectional view taken on the plane IV-IV of Figure 3.

As shown on the drawings:

While the drawings and the following description will refer to the installation of this invention in a railway car, it is to be distinctly understood that the invention is in no way limited to such specific application but may be equally well applied to any room area supplied by a ventilating system having certain characteristics as hereinafter set forth. Hence, the principle of this invention may be applied to auditoriums, assembly halls, theaters, private and commercial building structures, street cars, motor buses, etc.

vl'teferring to Figure 1, there is shown a portion of :a railway car If! having a floor Mia and a roof Ib. A plurality of passenger seats II are arranged along the length of the car in conventional manner. The car I0 is provided with a well-known form of ventilating air distributing apparatus which forms the interior ceiling of the car illustrated. The car roof is of conventional double walled construction, having an inner wall Inc spaced from the exterior wall .Ilib and the space therebetween is filled with a suitable heat insulating material I2. A pair of transversely spaced, vertically disposed walls I3 are provided which cooperate with the interior roof wall Iilc to define a ventilating distributing duct or plenum chamber I4 extending lengthwise of the car, Just under the roof. If the car is provided with a clerestory, the duct I4 may be disposed in it. As is more fully described in the above referred to patent to Damerel, No. 2,304,628, the duct I A defines a plenum chamber for a ventilating system for the interior of the car. Any suitable form of air pressuring means, such as a motor-driven blower I5, is mounted in the car with the outlet end thereof in communication with the duct or plenum chamber I l. Hence, the air in the plenum chamber is maintained at a slightly higher pressure than that existing in the interior of the car and tends to flow from the plenum chamber l4 into the interior of the car. It will be understood that the air supplied to the plenum chamber I4 may be heated or cooled by conventional apparatus according to the requirements of the outdoor temperature.

To uniformly distribute the ventilating air from the plenum chamber into the interior of the entire car, an air distributing unit is provided consisting essentially of a control panel I6 and distributing panel IT. The control panel IS in efiect defines the bottom wall of the duct or plenum chamber I4 and is provided with a plurality of longitudinally spaced transversely extending openings Ifia through which air may flow downwardly from the distributing duct or plenum chamber I4 into the space between the panels I6 and H. The rate of air flow is controlled by a valve plate or shutter I8, adjustable in vertical position relative to each opening I Get by means of a threaded shaft I9. Cradles 20 are provided on each end of the valve plates I9 and maintain a tension on the threaded spindle and prevent rattling of the valve plate I8. The bottomend of the spindle I9 is provided with an enlarged head E941 defining a socket-like recess which ,is accessible from the interior of the car through a suitable aperture I'Ib in the distributing panel I! to receive a correspondingly shaped head of an adjusting tool 20. Hence, each of the valve plates I8 along the length of the car may be adjusted in vertical position so as to provide a substantially uniform flow of air into the interior of the car along the entire length thereof, irrespective of the location of the motordriven blower I5. Obviously, those openings Ifia which are located closer to the discharge end of the motor of the blower I5 will have their effective passage area more reduced by the valve plates I8 than the openings Ita which are more remotely disposed.

Immediately beneath each of the openings Ifia, a baffle device 23 is provided which operates to diffuse the stream of air passing downwardly from the distributing duct I4 through the opening IBa. The baffle 23 is of perforated construction having a plurality of apertures 23a therein, and. is of triangular configuration in vertical cross-section. A perforated support plate 24 is supported horizontally within each baffle 23 and in turn mounts a bracket 24a through which the control rod l 9 passes and against which the control rod head I 9a abuts. The air distributing panels H are mounted in any convenient manner immediately beneath the control panels I8 and the baflles 23. The air distributing panels 51 are of perforated, sheet-like construction being provided with a large number of spaced perforations I'Ia. In addition, a large aperture I'Ia is provided in alignment with each control shaft I9 for access thereto and this opening is normally closed by a removable plug I'Ic (Figure 3). Hence, the controlled rate of flow of ventilating air through each of the openings Ita in the control panel I5 is further diffused by passage through the perforations Ila of the distributing panel IT.

The construction thus far described represents merely-a well-known form of ventilating "arrangement which has found wide application in railway cars and similar ventilated enclosures. In accordance withthis invention, advantage is taken of the uniform air distributing characteristics of the aforedescribed ventilating arrangement to produce a uniform distribution of sound energy throughout the interior of the space served by the ventilating arrangement with a minimum number of loudspeakers. In accordance with this invention, one or more loudspeaker units 25 are mounted within the plenum chamber or distributing duct I l of the ventilating system. By so mounting the loudspeaker units, it has been found that the sound energy generated thereby is more uniformly transmitted throughout the entire area of the enclosure served by the ventilating system. This desirable result is undoubtedly primarily attributable to the fact that the sound energy produced by the loudspeaker is primarily transmitted to the interior of the car through the controlled area passages provided by the ventilating system. Hence, when a loudspeaker unit 25 is mounted adjacent one end of the car, for example adjacent one of the transverse bulkheads Illd customarily provided in railway car construction, there is a relatively small passage area for sound transmission through the control panel openings I6a which are located immediately adjacent that end of the car, as determined by the setting of the plates I8. Further along the length of, the car, the effective area of the openings Ilia, as

determined by the setting of the plates l8, is

gradually increased so that proportionately more sound energy is transmitted through these openings although, of course, the intensity of the sound energy at such point will be reduced as a greater function of the distance from the one loudspeaker 25. But at such point there will also be a contribution in energy from the other loudspeaker. In any event, it will be found that the distribution of sound energy throughout the interior area served by the ventilating system is greatly improved. In the particular application of the loudspeaker arrangement to a railway car, it has been found that the mounting of a speaker at each end of the car, for example on or adjacent each of the two transverse bulkheads Hlb, will provide a very satisfactory sound energy level throughout the entire interior of the car, so that all passengers may comfortably receive and comprehend the sound energy produced by the loudspeaker.

It should be further noted that the arrangement of the loudspeaker unit in the manner described has the further advantage of making the location of the loudspeaker practically impossible to detect by ear. This eliminates the normal tendency of the occupants of the car to stretch, strain, and look around in an attempt to locate the source of the sound reaching their ears. Furthermore, no special mounting arrangements are required for the loudspeaker and a much more economical loudspeaker construction may be utilized by virtue of the complete elimination of any fancy trappings or casings which have been heretofore required to conceal the loudspeaker when disposed in the interior of the car.

Accordingly, it will be apparent to those skilled in the art that this invention provides a greatly improved loudspeaker arrangement for ventilated spaces and, in the particular application to a railway car, will not only greatly reduce the initial installation cost of a loudspeaker system but will provide a more uniform distribution of sound energy throughout the car and provide the optimum in listener comfort.

It will, of course, be understood that various details of construction may be modified through a wide range without departing from principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claim.

chambers, blower means at one end of said first duct means providing a supply of pressurized ventilating air to one end of said primary plenum chamber, a first speaker unit in said primary plenum chamber adjacent said blower means to transmit an audible sound signal into the stream of pressurized air flowing from said blower means, adjustable control means between each of said secondary plenum chambers and said primary plenum chamber, each of said control means adjusted to provide an opening between said secondary plenum chambers and said primary plenum chamber of progressively increased relative size in relation to the distance each opening is removed from the blower means to flow air from said primary plenum chamber into said secondary plenum chambers at reduced velocity and pressure, a second speaker unit in said primary plenum chamber at the other end thereof to transmit a supplementary audible sound signal into the stream of pressurized air flowing through said openings, and passageways between each of said secondary plenum chambers and said space to permit air flow therebetween, whereby the supply of ventilating air and sound energy will be concurrently uniformly distributed throughout the space.

GEORGE K. RAIDER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,051,687 Clark Jan. 28, 1913 1,823,479 Venderbush Sept. 15, 1931 1,952,514 Selby Mar. 27, 1934 2,017,153 Kellogg Oct. 15, 1935 2,172,771 Norris Sept. 12, 1939 2,218,212 Nassos Oct. 15, 1940 2,251,682 Leadbetter Aug. 5, 1941 2,304,628 Damerel Dec. 8, 1942 

